Tobamovirus

Taxobox | color=violet


image_width =
image_caption =
name = "Tobamovirus"
virus_group = iv
familia = "None Currently Assigned"
genus = "Tobamovirus"

The genus Tobamovirus contains viruses with a positive sense RNA genome that infect plants. The most common tobamovirus is probably tobacco mosaic virus, which infects tobacco and other plants including potatoes, tomatoes, and squashes. The name "Tobamovirus" comes from the host and symptoms: Toba for Tobacco and mo for mosaic. There are four subgroups within this genus; the solanaceous, brassicas, cucurbits and malvaceous-infecting tobamoviruses. The main differences between these groups are genome sequence and range of host plants.

Genome

The RNA genome encodes four polypeptides; the non-structural protein and the read through product which are involved in virus replication, the movement protein which is necessary for the virus to move between cells and the coat protein. The virus is able to replicate without the movement or coat proteins but the other two are essential. The non-structural protein has domains suggesting it is involved in RNA capping and the read through product has a motif for an RNA polymerase. The movement proteins are made very early in the infection cycle and localized to the plasmodesmata, they are probably involved in host specificity as they are believed to interact with some host cell factors.

Routes of Infection

The infection is localized to begin with but if the virus remains unchallenged it will spread via the vascular system into a systemic infection. The exact mechanism the virus uses to move throughout the plant is unknown but the interaction of pectin methylesterase, a cellular enzyme important for cell wall metabolism and plant development, with the movement protein has been implicated.

Members

Definitive members of the Tobamovirus group: [ [http://www.dpvweb.net/dpv/showdpv.php?dpvno=184 Descriptions of Plant Viruses, The Association of Applied Biologists (AAB)] ]
*Tobacco mosaic virus (TMV)
*Cucumber green mottle mosaic virus (CGMMV) and Cucumber virus 4 (CV4)
*Frangipani virus (FV)
*Odontoglossum ringspot virus (ORSV)
*Ribgrass mosaic virus (HRV)
*Sammons' opuntia virus (SOV)
*Sunn-hemp mosaic virus (SHMV)
*Tomato mosaic virus (ToMV) and U2 - tobacco mosaic virus (T2MV)

Tentative members of the Tobamovirus group include:
*Beet necrotic yellow vein virus (BNYVV)
*Chara corallina virus (CCV)
*Nicotiana velutina mosaic virus (NVMV)
*Peanut clump virus (PCV)
*Potato mop-top virus (PMTV)
*Soil-borne wheat mosaic virus (SBWMV)

Footnotes

References

Cactus mild mottle virus is a new cactus-infecting tobamovirusBE Min, BN Chung, MJ Kim, JH Ha, BY Lee, KH Ryu - Archives of Virology, 2006 [http://www.springerlink.com/content/u3n622011035x205/fulltext.pdf]

Subcellular localization of host and viral proteins associated with tobamovirus RNA replication - Yuka Hagiwara, Keisuke Komoda, Takuya Yamanaka, Atsushi Tamai, Tetsuo Meshi, Ryo Funada, Tomohiro Tsuchiya, Satoshi Naito and Masayuki Ishikawa [http://www.nature.com/emboj/journal/v22/n2/abs/7594944a.html]

Systemic movement of a tobamovirus requires host cell pectin methylesteraseMin-Huei Chen and Vitaly Citovsky - The Plant Journal Volume 35 Issue 3 Page 386 - August 2003 [http://www.blackwell-synergy.com/doi/pdf/10.1046/j.1365-313X.2003.01818.x?cookieSet=1]